1. Technical Field
The present disclosure relates to methods for making carbon nanotube paper and, more particularly, to a method for making high-density, oriented carbon nanotube paper.
2. Description of Related Art
Generally, carbon nanotubes prepared by conventional methods are in particle or powder forms. The particle or powder-formed carbon nanotubes limit the applications of the carbon nanotubes. Thus, the carbon nanotubes need to form meso- or macro-scale structures for practical applications in various fields.
The carbon nanotube paper is a macro-scale structure which retains the excellent physical properties of carbon nanotubes. Therefore, it has great potential applications in heat-dissipation structures, electrical-conducting structures and thermal-conducting structures.
Generally, the carbon nanotube paper is made by wet method, which mainly includes modification, dispersion, filtration, and drying to form the carbon nanotube paper. An example is shown and discussed in U.S. Publication. No. 20110300031A1, entitled, “MANUFACTURING CARBON NANOTUBE PAPER,” published to Kim, et al. on Dec. 8, 2011. This patent application discloses an apparatus for making carbon nanotube paper and a method for making carbon nanotube paper using the apparatus. The method in this publication includes preparing carbon nanotube colloidal solution, preparing structure having relatively sharp edge, immersing structure into carbon nanotube colloidal solution, and withdrawing structure from carbon nanotube colloidal solution.
However, the orientation of carbon nanotubes in the carbon nanotube paper made by the method is undefined, and the carbon nanotube paper is disordered, due to the evenly dispersion of the carbon nanotubes into solvent. Additionally, the density of carbon nanotubes in the carbon nanotube paper is low, which affects the mechanical and conducting properties of the carbon nanotube paper.
What is needed, therefore, is to provide a method for making carbon nanotube paper that has a high density and is directional.